EP4631063A1

EP4631063A1 - Reactor core construction systems and methods

Info

Publication number: EP4631063A1
Application number: EP23901336.0A
Authority: EP
Inventors: Bojan Petrovic
Original assignee: Georgia Tech Research Institute; Georgia Tech Research Corp
Current assignee: Georgia Tech Research Institute; Georgia Tech Research Corp
Priority date: 2022-12-07
Filing date: 2023-11-29
Publication date: 2025-10-15
Also published as: WO2024123577A1

Abstract

In many embodiments, a plurality of neutron moderators may be arranged to define a plurality of flow channels within a reactor vessel, wherein each neutron moderator of the plurality of neutron moderators includes at least one surface face, and each neutron moderator is not machined. In some embodiments, the flow channel may be defined by the at least one surface face of each neutron moderator of the plurality of neutron moderators. In at least one embodiment, the plurality of neutron moderators may include at least three neutron moderators. In several embodiments, the plurality of neutron moderators may include a first pair of neutron moderators and a second pair of neutron moderators. In one or more embodiments, the first pair of neutron moderators and the second pair of neutron moderators may be arranged to form a lattice configuration in a reactor vessel.

Description

REACTOR CORE CONSTRUCTION SYSTEMS AND METHODS

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Non-Provisional Application No. 18/062,888, filed December 7, 2022, entitled "REACTOR CORE CONSTRUCTION SYSTEMS AND METHODS," which is incorporated herein in its entirety for all purposes.

TECHNICAL FIELD

[0002] This disclosure relates generally to methods and systems for constructing a nuclear reactor core.

BACKGROUND

[0003] Nuclear reactors require neutrons to propagate nuclear chain reactions and maintain an operational status of the reactor. Neutrons are released during both fission and fusion reactions. However, the neutrons released from these reactions generally have too much kinetic energy to reliably propagate nuclear chain reactions. A neutron moderator may therefore be used to reduce the kinetic energy of neutrons released from the reactions and increase the probability of the nuclear chain reaction continuing.

[0004] Several types of moderating materials have been used. Heavy water and light water are common moderating materials in some types of reactors. When used in conjunction with other substances (e.g., various types of coolants), the combination may present safety issues. Graphite, hydrides, and other solid moderators may be used safely in certain types of reactors, but present high cost barriers due to high-cost machining needed to shape the solid moderators.

[0005] Therefore, there is a long-felt but unresolved need for methods and systems of configuring moderators inside a nuclear reactor core without the use of high-cost machining while retaining performance metrics.

SUMMARY

[0006] An arrangement of neutron moderators may include a first pair of neutron moderators and a second pair of neutron moderators. The first and second pair of neutron moderators may cooperate to form a flow channel with at least a portion of a respective face of each neutron moderator of the first pair of neutron moderators and a respective face of each neutron moderator in the second pair of neutron moderators. The first pair of neutron moderators and the second pair of neutron moderators may be arranged to define a square, rectangular, triangular, hexagonal, or other regular lattice configuration in a reactor vessel and along a plane perpendicular to the flow channel.

[0007] In some embodiments, each neutron moderator of the first pair of neutron moderators may include an elongated first neutron moderator body defining four sides. Each of the four sides may be connected to one another to define a perimeter of the respective neutron moderator of the first pair. Each side may extend along an elongated direction of the elongated first neutron moderator body. Each neutron moderator of the second pair of neutron moderators may include an elongated second neutron moderator body defining four sides. Each side of the four sides may be connected to one another, defining a perimeter of the respective neutron moderator of the second pair, each side extending along an elongated direction of the elongated second neutron moderator body. At least a portion of a face of each neutron moderator of the first pair of neutron moderators and each neutron moderator of the second pair of neutron moderators is on a single side of a respective neutron moderator structure.

[0008] In some embodiments, each side of the four sides of each neutron moderator of the first pair of neutron moderators may have a width that is uniform along the elongated direction and that is uniform with the other sides of the respective neutron moderator. The four sides of each respective neutron moderator may define a square cross section. Similarly, each side of the four sides of each neutron moderator of the second pair of neutron moderators may have a width that is uniform along the elongated direction and that is uniform with the other sides of the respective neutron moderator. The four sides of each respective neutron moderator may define a square cross section.

[0009] In some embodiments, the flow channel may have a rectangular cross-section. The rectangular cross-section may be defined by an entire surface area of a respective side of each neutron moderator of the first pair of neutron moderators and a portion of the second pair of neutron moderators. [0010] In some embodiments, each neutron moderator of the first pair of neutron moderators may have a first cross-sectional shape. Each neutron moderator of the second pair of neutron moderator may have a second cross-sectional shape. The first pair of neutron moderators and the second pair of neutron moderators may cooperate with one another to define the flow channel as having a rectangular cross-section.

[0011] In some embodiments, at least a portion of each neutron modulator in the first pair of neutron moderators may include a generally planar region of the respective neutron moderator. Similarly, at least a portion of each neutron modulator in the second pair of neutron moderators may include a generally planar region of the respective neutron moderator. The generally planar region may include a flat surface of the respective neutron moderator.

[0012] In some embodiments, each neutron moderator of each of the first pair of neutron moderators and the second pair of neutron moderators include at least one connector body. The connector body may be arranged at an end of a respective neutron moderator. The at least one connector body is configured to mount the respective neutron moderator in a gridplate of the reactor vessel.

[0013] A reactor vessel system may include a reactor vessel defining a reactor vessel volume. The system may also include an arrangement of neutron moderators arranged in the reactor volume. The arrangement may include a first pair of neutron moderators and a second pair of neutron moderators. The first and second pair of neutron moderators may cooperate to form a flow channel with at least a portion of a respective face of each neutron moderator of the first pair of neutron moderators and a respective face of each neutron moderator in the second pair of neutron moderators. The first pair of neutron moderators and the second pair of neutron moderators may be arranged to define a square, rectangular, triangular, hexagonal, or other regular lattice configuration in a reactor vessel and along a plane perpendicular to the flow channel.

[0014] In some embodiments, the reactor vessel system may include a gridplate in the reactor vessel. The gridplate may arrange each neutron moderator of the first pair of neutron moderators and the second pair of neutron moderators in a lattice configuration, such as any of the lattice configurations described herein. The reactor vessel may include a substantially rectangular crosssection along an elongated length of the reactor vessel. The reactor vessel system may include a peripheral neutron moderator having a substantially rectangular cross-section. The peripheral neutron moderator may define a transition between an interior vessel wall of the reactor vessel and one or more neutron moderators of the first pair of neutron moderators and/or the second pair of neutron moderators.

[0015] A reactor vessel system may include a reactor vessel defining a reactor vessel volume. The reactor vessel system may also include a first pair of neutron moderators. The reactor vessel system may also include a second pair of neutron moderators that cooperate with the first pair of neutron moderators to define a flow channel therebetween. At least a portion of a respective flat face of each neutron moderator of the first pair of neutron moderators and the second pair of neutron moderators may define the flow channel.

[0016] In some embodiments, the reactor vessel may define an elongated structure having a first end and a second end opposite the first end. The flow channel may include a square or a rectangular cross-section along an entire length of each neutron moderator in the first pair of neutron moderators and each neutron moderator in the second pair of neutron moderators. The first pair of neutron moderators and the second pair of neutron moderators may include a plurality of neutron moderators. The plurality of neutron moderators may define, collectively, a plurality of flow channels. The plurality of neutron moderators may also establish, collectively, a lattice configuration (e.g., a square, rectangular, triangular, hexagonal, or other regular lattice configuration) on a plane perpendicular to the plurality of flow channels.

[0017] In some embodiments, the reactor vessel system may include a reactor vessel having a rectangular cross-section. The plurality of neutron moderators may include a sub-plurality of neutron moderators about a periphery of the plurality of neutron moderators. The plurality of neutron moderators may be arranged to define an interface with flat, internal vessel walls of the reactor vessel along the rectangular cross-section.

[0018] A method of constructing a reactor system may include providing a reactor vessel.

The reactor vessel may include a reactor vessel volume. The method may also include arranging a support structure within the reactor vessel. The support structure may include a series of mounts configured to secure neutron moderators thereto. The method may also include securing a first pair of neutron moderators to the support structure. The method may also include securing a second pair of neutron moderators to the support structure. At least a portion of a face of each neutron moderator of the first pair of neutron moderators and a portion of a face of each neutron moderator of the second pair of neutron moderators may define a flow channel through the reactor vessel volume.

[0019] In some embodiments, the method may include maintaining an arrangement of the first pair of neutron moderators and the second pair of neutron moderators in a lattice configuration (e.g., square, rectangular, triangular, hexagonal, or other regular lattice configuration). Such lattice configuration may be perpendicular to the flow channel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings illustrate one or more embodiments and/or aspects of the disclosure and, together with the written description, serve to explain the principles of the disclosure. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment, and wherein:

[0021] FIG. 1 A illustrates a vessel of a reactor system, according to one embodiment of the present disclosure;

[0022] FIG. IB illustrates a molten salt reactor system, according to one embodiment of the present disclosure;

[0023] FIG. 2A illustrates a front perspective view of an example neutron moderator, according to one embodiment of the present disclosure;

[0024] FIG. 2B illustrates a rear perspective view of the example neutron moderator of FIG. 2A;

[0025] FIG. 2C illustrates a front perspective view of an example neutron moderator, according to one embodiment of the present disclosure;

[0026] FIG. 2D illustrates a rear perspective view of the example neutron moderator of FI. 2C;

[0027] FIG. 3 A illustrates a side, cross-sectional view of a plurality of example neutron moderators within the reactor vessel of FIG. 1A, taken along line 3A-3A of FIG. 1A, according to one embodiment of the present disclosure; [0028] FIG. 3B illustrates another side, cross-sectional view of a plurality of example neutron moderators within the reactor vessel of FIG. 1A, taken along line 3B-3B of FIG. 1A, according to one embodiment of the present disclosure;

[0029] FIG. 4A illustrates a perspective view of an example neutron moderator arrangement configured within a reactor core, according to one embodiment of the present disclosure;

[0030] FIG. 4B illustrates a cross-sectional view the arrangement of FIG. 4 A, taken along line 4B-4B of FIG. 4A, according to one embodiment of the present disclosure;

[0031] FIG. 5A illustrates a perspective view of an example neutron moderator arrangement configured within a reactor core, according to one embodiment of the present disclosure;

[0032] FIG. 5B illustrates a cross-sectional view the arrangement of FIG. 5 A, taken along line 5B-5B of FIG. 5 A, according to one embodiment of the present disclosure;

[0033] FIG. 6A illustrates a perspective view of an example neutron moderator arrangement configured within a reactor core, according to one embodiment of the present disclosure;

[0034] FIG. 6B illustrates a cross-sectional view the arrangement of FIG. 6 A, taken along line 6B-6B of FIG. 6A, according to one embodiment of the present disclosure;

[0035] FIG. 7 illustrates a cross-sectional view of the arrangement of FIG. 6A having flow channels offset from one another, according to one embodiment of the present disclosure;

[0036] FIG. 8A illustrates a perspective view of an alternative example neutron moderator arrangement configured within a reactor core, according to one embodiment of the present disclosure;

[0037] FIG. 8B illustrates a cross-sectional view the arrangement of FIG. 8 A, taken along line 8B-8B of FIG. 8 A, according to one embodiment of the present disclosure;

[0038] FIG. 9 illustrates a top view of an example arrangement of first neutron moderators and second neutron moderators within a reactor vessel, according to one embodiment of the present disclosure;

[0039] FIG. 10 illustrates a top view of an example arrangement of first neutron moderators and second neutron moderators within a reactor vessel, according to one embodiment of the present disclosure; [0040] FIG. 11 A illustrates a side view of a gridplate including a plurality of neutron moderators, according to one embodiment of the present disclosure;

[0041] FIG. 11B illustrates a side view of a gridplate including a plurality of neutron moderators, according to one embodiment of the present disclosure;

[0042] FIG. 12 illustrates a perspective view of a gridplate within a reactor vessel, according to one embodiment of the present disclosure; and

[0043] FIG. 13 depicts a flowchart of a method of constructing a reactor system.

[0044] The use of cross-hatching or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements and also to facilitate legibility of the figures. Accordingly, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, element proportions, element dimensions, commonalities of similarly illustrated elements, or any other characteristic, attribute, or property for any element illustrated in the accompanying figures.

[0045] Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto.

DETAILED DESCRIPTION

[0046] The description that follows includes sample systems, methods, and apparatuses that embody various elements of the present disclosure. However, it should be understood that the described disclosure may be practiced in a variety of forms in addition to those described herein.

[0047] Whether a term is capitalized is not considered definitive or limiting of the meaning of a term. As used in this document, a capitalized term shall have the same meaning as an uncapitalized term, unless the context of the usage specifically indicates that a more restrictive meaning for the capitalized term is intended. However, the capitalization or lack thereof within the remainder of this document is not intended to be necessarily limiting unless the context clearly indicates that such limitation is intended.

[0048] Nuclear reactors may utilize neutron moderators to sustain a nuclear chain reaction. At the same time, a reactor core of the nuclear reactor system must be cooled sufficiently to remove the generated useful heat as well as to prevent excessive heating of the system and other undesired effects of the system, which can ultimately cause safety concerns and lowered energy generation and other performance metrics. At least some nuclear reactors utilize solid neutron moderators within the reactor core. In many embodiments, the reactor core may include flow channels in the solid neutron moderators, which allows a coolant or molten fuel to traverse the reactor core and remove heat and maintain the reactor core temperature. Conventional solid neutron moderators may require machining to create specific shapes of flow channels in the moderators, leading to expensive manufacturing costs. Furthermore, different reactor types and reactor vessel types and shapes may require different solid neutron moderator shapes and sizes, meaning that the conventional moderators need to be precisely machined to create flow channels. Such conventional techniques may thus require expensive machining cost and may be susceptible to mechanical failure and/or suboptimal performance, particularly where such moderators deviate from design specifications.

[0049] To mitigate these and other challenges, disclosed herein includes example polygonal (or circular/cylindrical) neutron moderators that may be arranged in a manner to define a flow channel with sides or faces of adjacently arranged moderators, absent or free from any flow channel bore machining used in conventional designs. Rather than machine multiple boundaries of the flow channel into a surface of the moderator block or otherwise form a flow channel therethrough, the moderators of the present disclosure may utilize the main shape of the neutron moderator (e.g., a main body polygonal or circular/cylindrical shape) to form a boundary of the flow channel, and/or utilize a facet or face or planar-type cut to define a boundary of the flow channel. Such moderator block may then be positioned adjacent other, similarly constructed moderator blocks in order to define an arrangement of moderator blocks that collectively define a flow channel therebetween. In many embodiments, these neutron moderators may be suitable for more than one type of reactor or reactor vessel, simplifying manufacturing. [0050] In one or more embodiments, the neutron moderators may be elongated blocks of a neutron moderator material arranged within a nuclear reactor core (or reactor vessel). One or more flow channels may be defined by plurality of the neutron moderators along an elongated dimension of the moderators. In certain embodiments, the flow channels extend from a bottom portion of the reactor vessel to a top portion of a reactor vessel and are as long as the neutron moderators. In some embodiments, in the reactor core, a fluid flows through the reactor core through the flow channels in between the neutron moderators, and the fluid is heated due to the nuclear reactions taking place within the reactor core. In at least one embodiment, the fluid flows through the flow channels up through the reactor core and then flows out of the reactor core and reactor vessel to remove the heat from the reactor core.

[0051] In many embodiments, a plurality of neutron moderators may be arranged to define a flow channel within a reactor vessel, wherein each neutron moderator of the plurality of neutron moderators includes at least one surface face. In some embodiments, the flow channel may be defined by the at least one surface face of each neutron moderator of the plurality of neutron moderators. In at least one embodiment, the plurality of neutron moderators may include at least three neutron moderators. In several embodiments, the plurality of neutron moderators may include a first pair of neutron moderators and a second pair of neutron moderators. In one or more embodiments, the first pair of neutron moderators and the second pair of neutron moderators may be arranged to form a square, rectangular, triangular, hexagonal, or other regular lattice configuration in a reactor vessel.

[0052] Referring now to the figures, FIG. 1 illustrates an example vessel 102. The vessel 102 may be any appropriate vessel used with a nuclear reactor system. As described herein, the neutron moderators of the present disclosure may be arranged in the vessel 102. In some cases, the vessel 102 may be a reactor vessel of a molten salt reactor system, for example, as shown in FIG. IB; however, this is not required. With reference to FIG. IB, a schematic overview of one embodiment of a molten salt reactor system 100. The molten salt reactor system may implement and include an arrangement of neutron moderators, as described in greater detail below. As will be understood and appreciated, the example, schematic overview shown in FIG. IB represents merely one high temperature environment in which the plurality of neutron moderators and arrangements thereof may be utilized. It will be understood that the plurality of neutron moderators and arrangements thereof as described herein may be used in and with substantially any other nuclear reactor system, such as those associated with high temperatures and/or high pressures, among other characteristics, substantially analogous to those associated the molten salt reactor system 100 described herein.

[0053] In various embodiments, the molten salt reactor system 100 may utilize fuel salt enriched with uranium (e.g., high-assay low-enriched uranium) to create thermal power via nuclear fission reactions. In at least one embodiment, the composition of the fuel salt may be LiF-BeF2-UF4, though other compositions of fuel salts may be utilized as fuel salts within the reactor system 100. The fuel salt within the system 100 is heated to high temperatures (about 700 °C) and high pressure (about 100 psi), and the fuel salt melts as the system 100 is heated. In several embodiments, the molten salt reactor system 100 includes a reactor vessel 102 where the nuclear reactions occur within the molten fuel salt, a fuel pump 104 that pumps the molten fuel salt to a heat exchanger 106, such that the molten fuel salt re-enters the reactor vessel after flowing through the heat exchanger, and piping in between each component. The molten salt reactor system 100 may also include additional components, such as, but not limited to, drain tank 108 and reactor access vessel 110). The drain tank 108 may be configured to store the fuel salt once the fuel salt is in the reactor system 100 but in a subcritical state, and also acts as storage for the fuel salt if power is lost in the system 100. The reactor access vessel may be configured to allow for introduction of small pellets of uranium fluoride (UF4) to the system 100 as necessary to bring the reactor to a critical state and compensate for depletion of fissile material. It should be understood that the systems and methods described below may be used with the molten salt reactor system 100, as well as other suitable types of reactors. In at least one embodiment, the neutron moderators may be located in the reactor vessel 102 of the reactor system 100.

[0054] Turning now to FIGS. 2 A and 2B, a front perspective view and a rear perspective view of an example neutron moderator 200 is shown, respectively, according to one embodiment of the present disclosure. In various embodiments, as shown in FIG. 2A, a neutron moderator 200 may include a neutron moderator body 221. The neutron moderator body 221 may include four approximately equal sides, such as a first side 223a, a second side 223b, a third side 223c, and a fourth side 223d, as illustrated in FIGS. 2Aand 2B. Each of the sides 223a-223d may define a face, such that the body 221 has a first face 225a at a first side 223a, a second face 225b at a second side 223b, a third face 225c at a third side 223c, and a fourth face 225d at a fourth side 223d. Each face 225a-225d may be a generally planar surface of the body 221 at the respective side. In some cases, each face 225a-225d may be a generally flat or generally uninterrupted surface of the body 221, which as described in greater detail below, may be used to define a boundary of a flow channel within the reactor vessel. In several embodiments, the body 221 may also include a top side 227 that defines a top face 229, and a bottom side 231 that defines a bottom face 233. In at least one embodiment, the top face 229 and the bottom face 233 may be a generally planar surface of the body at the respective top side 227 and bottom side 231. In certain embodiments, the moderator body 221 may have a body height 210, a body width 211, and a body depth 212 (Z, Y, X directions, respectively).

[0055] In multiple embodiments, the moderator body 221 may define a plurality of edges and corners. Specifically, in one or more embodiments, the moderator body 221 may define edges 235 (e.g., edges 235a, 235b, 235c, and 235d) at the intersection between two sides 223 (e.g., the intersection of side 223a and side 223b form edge 235a), and may also define edges 237 (edges 237a, 237b, 237c, 237e, 237f, 237g, and 237h) at the intersection between a side 223 and either the top side 227 or the bottom side 231 (e.g., the intersection of side 223a and top side 227 form edge 237a). In many embodiments, the moderator body 221 may define a corner 239 (e.g., corners 239a, 239b, 239c, 239d, 239e, 239f, 239g, and 239h) at the intersecting point between three sides, such as between two sides 223 and either the top side 227 or bottom side 231. For example, in one embodiment, the point at which side 223a, 223b, and bottom side 231 intersect may be defined as corner 239e. In at least one embodiment, the edges 235 and 237, and corners 239, may be rounded or at an angle. In some embodiments, the edges 235 and 237 may include a series of several surfaces that define a transition from the first surface (e.g., face 225a) that defines the edge to the second surface (e.g., face 225b) that defines the edge (e.g., edge 235a).

[0056] In several embodiments, the moderator body 221 may be defined by the body height 210, the body width 211, and the body depth 212. In one or more embodiments, at least a portion of each of the faces 225 of the moderator body 221 may include a generally planar region. In some embodiments, the generally planar regions of the faces 225 of moderator body 221 may be flat; machined only to the extent required to initially cut or shape the structure to the desired dimensions. In some cases, the flat surface may be machined (e.g., polished), although no drilling of holes is required. Although FIG. 2A is shown as having four equal faces 225, and thus having a cross-sectional area of a square, other configurations are contemplated herein. For example, the neutron moderator 200 may have a cross-sectional area of a rectangle (as shown in FIG. 2B), an octagon (as shown in FIGS. 8A and 8B), a triangle, or any other polygonal shape. In an alternative embodiment, the neutron moderator 200 may have a cross-sectional area of a circle, such that the moderator 200 only has one side 223 and one surface 225, and flow channels are created by arranging a plurality of circular moderators 200 in a lattice (e.g., square lattice, triangular lattice, etc.).

[0057] In various embodiments, the neutron moderator 200 may be configured to achieve a certain set of performance metrics, both individually and when used as part of an arrangement of neutron moderators within a reactor core. In at least one embodiment, the neutron moderator 200 may be constructed from one or more materials including graphite, beryllium, beryllium oxide, hydrides, and other suitable materials. In some embodiments, the performance metrics may include a thermal or epithermal neutron spectrum, other thermal metrics, and other relevant metrics. In certain embodiments, the performance metrics may be achieved by adjusting parameters associated with the neutron moderator 200 including the shape of the neutron moderator 200, the body height 210, the body width 211, the body depth 212, and the composition of the neutron moderator 200 (e.g., graphite, beryllium, etc.). In other embodiments, the performance metrics (neutronics and thermal hydraulics) may be achieved by adjusting a width or height of the flow channel, as described in greater detail herein. For example, the volume ratio of the moderator and coolant can be defined by adjusting a width and a depth of the neutron moderators 200 in a given arrangement.

[0058] In some embodiments, the neutron moderator 200 may also include a first connector body 202 and a second connector body 204. In certain embodiments, the first connector 202 may be connected to the top side 227 of the moderator body 221, and the second connector 204 may be connected to the bottom side 231 of the moderator body 221. In many embodiments, the first connector body 202 and the second connector body 204 may allow the neutron moderator 200 to connect to a respective gridplate (as shown in FIGS. 11 A, 11B, and 12) at an associated end of the moderator body 221. In at least one embodiment, the first connector body 202 and the second connector body 204 may be manufactured from the same neutron moderator material(s) as the moderator 200 or may be made from another material, such as stainless steel, that does not present any safety concerns while installed within the reactor vessel. In one or more embodiments, the first connector body 202 and the second connector body 204 may be configured to attach to the respective gridplate(s) via press fit, threaded connection, or any other suitable method of connection. In one embodiment, although the neutron moderator 200 is shown as including both the first connector body 202 and the second connector body 204, the neutron moderator 200 may include only one connector body or no connector bodies.

[0059] Now turning to FIGS. 2C and 2D, a front perspective view and a rear perspective view of an example neutron moderator 200' is shown, according to one embodiment of the present disclosure. As shown in FIGS. 2C and 2D, in several embodiments, the neutron moderator 200' may be substantially analogous to the neutron moderator 200 of FIGS. 2A and 2B and include, for example: body 221' having a body height 210', a body width 211', and a body depth 212', a first side 223a', a second side 223b', a third side 223c', and a fourth side 223d', a first face 225a' at a first side 223a', a second face 225b' at a second side 223b', a third face 225c' at a third side 223c', and a fourth face 225d' at a fourth side 223d', a top side 227' having a top face 229', a bottom side 231' having a bottom face 233', edges 235' (e.g., edges 235a', 235b', 235c', and 235d') at the intersection between two sides 223' (e.g., the intersection of side 223a' and side 223b' form edge 235a'), edges 237' (edges 237a', 237b', 237c', 237e', 237f, 237g', and 237h') at the intersection between a side 223' and either the top side 227' or the bottom side 231' (e.g., the intersection of side 223a' and top side 227' form edge 237a'), and corners 239' (e.g., corners 239a', 239b', 239c', 239d', 239e', 239f, 239g', and 239h') at the intersection of an edge 235' and two adjacent edges 237'; redundant explanation of which is omitted herein for clarity.

[0060] Notwithstanding the foregoing similarities, the neutron moderator 200' is shown as having a rectangular cross section, rather than the square cross section of neutron moderator 200. Because of the rectangular cross-section of neutron moderator 200', two sides 223' (e.g., sides 223a' and 223c') are elongated as compared to the adjacent shorter sides 223' (e.g., sides 223b' and 223d'). Stated differently, the moderator 200' has a different body depth 212' than the moderator 200. Thus, the neutron moderator 200' may include the same components and features shown in FIG. 2A and perform similar functions.

[0061] Although FIGS. 2C and 2D shows the body depth 212' of moderator 200' as being greater than the body width 211 ', other configurations are contemplated. In some embodiments, the body width 211 may be greater than the body depth 212. The aspect ratio of the moderator 200' may also be different than what is shown. A specific body width-to-body depth ratio may be of any ratio (e.g., 2: 1, 1 :2, 3:2, etc.). The specific body width-to-body depth ratio may be determined to achieve a certain set of performance metrics, including a thermal or epithermal neutron spectrum, other thermal metrics, and other relevant metrics.

[0062] Now turning to FIGS. 3 A and 3B, side views a plurality of neutron moderators 301 forming flow channels 302 inside the reactor vessel 102 are shown, according to one embodiment of the present disclosure. In various embodiments, as shown in FIGS. 3A and 3B, the neutron moderators 301 may be substantially analogous to the neutron moderators 200 and 200' in FIGS. 2A and 2B. Thus, in many embodiments, the neutron moderators 301 may include some or all of the components and functionality of the neutron moderator 200. The reactor vessel 102 may be associated with a molten salt reactor system or a gas-cooled reactor system (e.g., VHTR, NGNP, or HTGCR). While the reactor vessel 102 is illustrated as being substantially cylindrical, in other cases a substantially polygonal reactor vessel may be used, such as the reactor vessel 1003 in FIG. 10.

[0063] In multiple embodiments, the neutron moderators 301 may be arranged within the reactor vessel 102 such that the flow channels 302 are defined by the respective faces of the neutron moderators 301. In many embodiments, the dimensions associated with the flow channels 302 may be defined by respective faces of the neutron moderators 301. In certain embodiments, the flow channels 302 may be configured such that molten salt or another suitable coolant may pass through the flow channels 302 to achieve certain performance metrics within the reactor core 300. In one embodiment, the performance metrics may include a thermal or epithermal neutron spectrum, other thermal metrics, and other relevant metrics.

[0064] In several embodiments, the reactor vessel 102 may have a vessel height 313. In at least one embodiment, the neutron moderators 301 may have a height that is equal to or lesser than the vessel height 313. In FIG. 3A, the moderators 301, the flow channels 302, and the reactor vessel 102 are illustrated in a two-dimensional plane (Z-Y plane), showing the body height 310 and the body depth 311 of the moderators 301. In FIG. 3B, the moderators 301, the flow channels 302, and the reactor vessel 102 are illustrated in a two-dimensional plane (Z, X plane) showing the body height 310 and the body width 312 of the moderators 301. Thus, the flow channels 302 appear wider in FIG. 3B than in FIG. 3A. [0065] Although FIGS. 3A and 3B show the flow channels 302 wider than deeper, other configurations are contemplated. By configuring the neutron moderators 301 that have differing body widths 310 and body depths 312 and varying the arrangement of the neutron moderators 301 within the reactor vessel 300, the flow channels 302 may be configured to have any number of differing dimensions. Thus, the flow channels 302 may be designed to achieve any number of predetermined parameters.

[0066] Turning now to FIGS. 4A and 4B, a perspective view and a cross-sectional view along line 4B-4B of FIG. 4A of an example neutron moderator arrangement 400 is shown, according to one embodiment of the present disclosure. In various embodiments, the neutron moderator arrangement 400 may include a plurality of any of the neutron moderators disclosed herein, such as a plurality including multiple moderator 200 components that are arranged with one another, as shown in FIGS. 4A and 4B. In some embodiments, each of the neutron moderators 200 in arrangement 400 are substantially analogous to the neutron moderator 200 in FIG. 2A. Although arrangement 400 of FIGS. 4A and 4B is shown having certain numbers of neutron moderators 200, it will be appreciated that arrangement 400 may have any number of neutron moderators 200, including a number of neutron moderators 200 that may fill to capacity a reactor vessel. The perspective view of the arrangement 400 illustrated in FIG. 4A is for purposes of illustration only. The neutron moderators 200 may generally be arranged within a reactor vessel such that respective flow channels of the arrangement 400 extend in a vertical direction; however, in other examples, the flow channels may extend in any appropriate direction as needed for a given application.

[0067] In multiple embodiments, the neutron moderators 200 of arrangement 400 may be attached to a gridplate and arranged to form a first pair of neutron moderators 441 and a second pair of neutron moderators 451. In some embodiments, at least a portion of a respective face of each neutron moderator 200 in the first pair of neutron moderators 441 and a respective face of each neutron moderator 200 in the second pair of neutron moderators 451 may be on a single side of a respective neutron moderator. In many embodiments, at least a portion of a respective face of each neutron moderator 200 in the first pair of neutron moderators 441 and a respective face of each neutron moderator 200 in the second pair of neutron moderators 451 may define a flow channel 402. In certain embodiments, the first pair of neutron moderators 441 and the second pair of neutron moderators 451 may be arranged to cooperate to form a lattice pattern in a plane perpendicular to the flow channel 402 (e.g., a square, rectangular, triangular, hexagonal, or other regular lattice configuration). Specifically, in one embodiment, the neutron moderators 200 of the first pair 441 are opposite each other across the flow channel 402, and the neutron moderators 200 of the second pair 451 are opposite each other across the flow channel 402 and adjacent to the moderators 200 of the first pair 441.

[0068] In several embodiments, as shown in FIG. 4B, the flow channel 402 may be specifically defined by flow channel walls 404, 408, 412, and 416. In at least one embodiment, the flow channel walls 404 and 408 may be defined by an entire face 225 of the moderator 200, such as any of the first face 225a, second face 225b, third face 225c, and fourth face 225d. In some embodiments, the flow channel walls 412 and 416 may be defined by a portion of a face 225 of the moderator 200, such as any of the first face 225a, second face 225b, third face 225c, and fourth face 225d. In one or more embodiments, the arrangement 400 may also include engagement interfaces 420, 424, 428, and 432. In certain embodiments, the engagement interfaces 420, 424, 428, and 432 may be defined by a portion of the face of the moderator 200, such as any of the first face 225a, second face 225b, third face 225c, and fourth face 225d. In many embodiments, the engagement interfaces 420, 424, 428, and 432 may be a connection or contact between adjacent moderators 200, such as a moderator of the first pair 441 and a moderator of the second pair 451.

[0069] In several embodiments, as shown in FIG. 4B, the neutron moderators 200 may be characterized by an equal depth and width. Thus, in many embodiments, the neutron moderators 200 may include a square cross-section. In some embodiments, although FIG. 4B shows the neutron moderators 200 characterized by an equal depth and width, any aspect ratio of depth to width may be achieved (e.g., 2:1, 3: 1, .5: 1, etc.). In certain embodiments, the aspect ratio may be determined to achieve certain performance metrics including a thermal or epithermal neutron spectrum, other thermal metrics, and other relevant metrics. In one or more embodiments, the flow channels 402 may include a width, depth, and a height. In at least one embodiment, the width of a flow channel 402 may correspond to the dimensions of the flow channel walls 404 and 408 (e.g., a face 225 of a neutron moderator 200), and the depth of the flow channel 402 may correspond to the dimensions of the flow channel walls 412 and 416 (e.g., a portion of a face 225 of a neutron moderator 200). In one embodiment, the height of the flow channel 402 may correspond to the height 210 of the neutron moderator 200. In certain embodiments, the width and the depth of the flow channel 402 may be configured to or tuned to achieve certain performance metrics.

[0070] In many embodiments, each neutron moderator 200 may be utilized as a boundary for up to four flow channels 402, such that each face 225 of a neutron moderator 200 are separately utilized as a boundary for four different flow channels 402 (except for those neutron moderators 200 that are on the edge of the arrangement 400, which will only be utilized as a boundary for two or three different flow channels 402).

[0071] Turning now to FIGS. 5A and 5B, a perspective view and a cross-sectional view along line 5B-5B of FIG. 5A of an example neutron moderator arrangement 500 is shown, according to one embodiment of the present disclosure. In one or more embodiments, the arrangement 500 is formed by a plurality of any of the elongated neutron moderators disclosed herein, such as a plurality of including multiple neutron moderators 200' components that are arranged with one another, as shown in FIGS. 5A and 5B. In multiple embodiments, each neutron moderator 200' may be substantially analogous to the neutron moderator 200' in FIGS. 2C and 2D and be characterized by an unequal body width and body depth. Similarly, in several embodiments, the arrangement 500 may be substantially analogous to the arrangement 400, with the exception that arrangement 500 includes neutron moderators 200' rather than moderators 200. Although arrangement 500 of FIGS. 5A and 5B is shown having certain numbers of neutron moderators 200', it will be appreciated that arrangement 500 may have any number of neutron moderators 200', including a number of neutron moderators 200' that may fill to capacity a reactor vessel. The perspective view of the arrangement 500 illustrated in FIG. 5A is for purposes of illustration only. The neutron moderators 200' may generally be arranged within a reactor vessel such that respective flow channels of the arrangement 500 extend in a vertical direction; however, in other examples, the flow channels may extend in any appropriate direction as needed for a given application.

[0072] In various embodiments, the neutron moderators 200' of arrangement 500 may be attached to one or more gridplates and arranged to form a first pair of elongated neutron moderators 541 and a second pair of elongated neutron moderators 551, in a substantially similar fashion as arrangement 400. In some embodiments, at least a portion of a respective face of each neutron moderator 200' in the first pair of neutron moderators 541 and a respective face of each neutron moderator 200' in the second pair of neutron moderators 551 may be on a single side of a respective neutron moderator 200'. In many embodiments, at least a portion of a respective face of each neutron moderator 200' in the first pair of neutron moderators 541 and a respective face of each neutron moderator 200' in the second pair of neutron moderators 551 may define a flow channel 502. In certain embodiments, the first pair of neutron moderators 541 and the second pair of neutron moderators 551 may be arranged to cooperate to form a lattice pattern in a plane perpendicular to the flow channel 502 (e.g., a square, rectangular, triangular, hexagonal, or other regular lattice configuration). Specifically, in one embodiment, the neutron moderators 200' of the first pair 541 are opposite each other across the flow channel 502, and the neutron moderators 200' of the second pair 551 are opposite each other across the flow channel 502 and adjacent to the moderators 200 of the first pair 541.

[0073] In one or more embodiments, the flow channels 502 may be substantially analogous to the flow channels 402. For example, in several embodiments, as shown in FIG. 5B, the flow channel 502 may be specifically defined by flow channel walls 504, 508, 512, and 516. In at least one embodiment, the flow channel walls 504 and 508 may be defined by an entire face 225' of the moderator 200', such as any of the first face 225a', second face 225b', third face 225c', and fourth face 225d'. In some embodiments, the flow channel walls 512 and 516 may be defined by a portion of a face 225' of the moderator 200', such as any of the first face 225a', second face 225b', third face 225c', and fourth face 225d'. In one or more embodiments, the arrangement 500 may also include engagement interfaces 520, 524, 528, and 532. In certain embodiments, the engagement interfaces 520, 524, 528, and 532 may be defined by a portion of the face of the moderator 200', such as any of the first face 225a', second face 225b', third face 225c', and fourth face 225d'. In many embodiments, the engagement interfaces 520, 524, 528, and 532 may be a connection or contact between adjacent moderators 200', such as a moderator of the first pair 541 and a moderator of the second pair 551.

[0074] In many embodiments, each neutron moderator 200' may be utilized as a boundary for up to four flow channels 502, such that each face 225' of a neutron moderator 200' are separately utilized as a boundary for four different flow channels 502 (except for those neutron moderators 200' that are on the edge of the arrangement 500, which will only be utilized as a boundary for two or three different flow channels 502). In one or more embodiments, the first pair of neutron moderators 541 and the second pair of neutron moderators 551 may be configured to form a lattice pattern.

[0075] In several embodiments, as shown in FIG. 5B, each elongated neutron moderator 200' may be characterized by a much greater depth than width. Thus, the elongated neutron moderators 200' may include a rectangular cross-section. In some embodiments, although FIG. 5B shows the elongated neutron moderators 200' characterized by a greater depth than width, any aspect ratio of depth to width may be achieved (e.g., 2: 1, 3: 1, .5:1, etc.). In one or more embodiments, the aspect ratio may be determined to achieve certain performance metrics including a thermal or epithermal neutron spectrum, other thermal metrics, and other relevant metrics. In at least one embodiment, the flow channels 502 may include a width, depth, and a height. In certain embodiments, the width of a flow channel 502 may correspond to the dimensions of the flow channel walls 504 and 508 (e.g., a face 225' of a neutron moderator 200'), and the depth of the flow channel 502 may correspond to the dimensions of the flow channel walls 512 and 516 (e.g., a portion of a face 225' of a neutron moderator 200'). In one embodiment, the height of the flow channel 502 may correspond to the height 210' of the neutron moderator 200'. In certain embodiments, the width and the depth of the flow channel 502 may be configured to or tuned to achieve certain performance metrics.

[0076] In one or more embodiments, the resulting flow channels 502 are thus characterized by a greater width than depth. In other embodiments, the plurality of elongated neutron moderators 200' may be arranged such that each elongated neutron moderator 200' meets the adjacent elongated neutron moderators 501 at or near an edge of the adjacent elongated neutron moderators 200'. In that case, the resulting flow channels 502 may be characterized by a greater depth than width. Thus, in many embodiments, by staggering the placement of the elongated neutron moderators 200', any number of configurations of elongated flow channels 502 may be provided.

[0077] Turning now to FIGS. 6A and 6B, a perspective view and a cross-sectional view along line 6B-6B of FIG. 6A of an example neutron moderator arrangement 600 are shown, according to one embodiment of the present disclosure. In various embodiments, the arrangement 600 includes a first plurality of any of the neutron moderators disclosed herein, such as a plurality including multiple moderator 200 components, and a second plurality of any of the neutron moderators disclosed herein, such as plurality including multiple moderator 200' components, all of which are arranged with one another, as shown in FIGS. 6A and 6B. In many embodiments, each neutron moderator 200 may be substantially analogous to neutron moderator 200 of FIGS. 2A and 2B, and each neutron moderator 200' may be substantially analogous to neutron moderator 200' of FIGS. 2C and 2D. Further, in certain embodiments, the arrangement 600 is substantially analogous to arrangement 400 and to arrangement 500, except that arrangement 600 utilizes both moderators 200 and 200' instead of only one of the moderators (e g., either moderators 200 or moderators 200'). Accordingly, in certain embodiments, the moderators 200 and the moderators 200' may be manufactured from the same or different materials, including graphite, beryllium, beryllium oxide, hydrides, and other suitable materials. Although arrangement 600 of FIGS. 6A and 6B is shown having certain numbers of neutron moderators 200 and 200', it will be appreciated that arrangement 600 may have any number of neutron moderators 200 and 200', including a number of neutron moderators 200 and 200’ that may fill to capacity a reactor vessel. The perspective view of the arrangement 600 illustrated in FIG. 6A is for purposes of illustration only. The neutron moderators 200, 200' may generally be arranged within a reactor vessel such that respective flow channels of the arrangement 600 extend in a vertical direction; however, in other examples, the flow channels may extend in any appropriate direction as needed for a given application.

[0078] In various embodiments, the neutron moderators 200 and 200' of arrangement 600 may be attached to one or more gridplates and arranged to form a first pair of neutron moderators 641 and a second pair of neutron moderators 651, in a substantially similar fashion as arrangement 400 and arrangement 500. In at least one embodiment, the first pair of neutron moderators 641 may include two moderators 200', and the second pair of neutron moderators 651 may include two moderators 200. In some embodiments, at least a portion of a respective face of each neutron moderator 200' in the first pair of neutron moderators 641 and a respective face of each neutron moderator 200 in the second pair of neutron moderators 651 may be on a single side of a respective neutron moderator 200 or 200'. In many embodiments, at least a portion of a respective face of each neutron moderator 200' in the first pair of neutron moderators 641 and a respective face of each neutron moderator 200 in the second pair of neutron moderators 651 may define a flow channel 602. In certain embodiments, the first pair of neutron moderators 641 and the second pair of neutron moderators 651 may be arranged to cooperate to form a lattice pattern in a plane perpendicular to the flow channel 602 (e.g., a square, rectangular, triangular, hexagonal, or other regular lattice configuration). Specifically, in one embodiment, the neutron moderators 200' of the first pair 641 are opposite each other across the flow channel 602, and the neutron moderators 200 of the second pair 651 are opposite each other across the flow channel 602 and adjacent to the moderators 200' of the first pair 641.

[0079] In one or more embodiments, the flow channels 602 may be substantially analogous to the flow channels 402 and 502. For example, in several embodiments, as shown in FIG. 6B, the flow channel 602 may be specifically defined by flow channel walls 604, 608, 612, and 616. In at least one embodiment, the flow channel walls 604 and 608 may be defined by an entire face 225 of moderator 200, such as any of the first face 225a, second face 225b, third face 225c, and fourth face 225d, or face 225' of the moderator 200', such as any of the first face 225a', second face 225b', third face 225c', and fourth face 225d'. In some embodiments, the flow channel walls 612 and 616 may be defined by a portion of a face 225 of the moderator 200, such as any of the first face 225a, second face 225b, third face 225c, and fourth face 225d, or face 225' of the moderator 200', such as any of the first face 225a', second face 225b', third face 225c', and fourth face 225d'. In one or more embodiments, the arrangement 600 may also include engagement interfaces 620, 624, 628, and 632. In certain embodiments, the engagement interfaces 620, 624, 628, and 632 may be defined by a portion of the face 225 of moderator 200, such as any of the first face 225a, second face 225b, third face 225c, and fourth face 225d, or a portion of the face 225' of the moderator 200', such as any of the first face 225a', second face 225b', third face 225c', and fourth face 225d'. In many embodiments, the engagement interfaces 620, 624, 628, and 632 may be a connection or contact between adjacent moderators 200 and 200', such as a moderator 200' of the first pair 641 and a moderator 200 of the second pair 651.

[0080] In many embodiments, each neutron moderator 200 and moderator 200' may be utilized as a boundary for up to two flow channels 602, such that two faces 225 of a neutron moderator 200 and two faces 225' of a neutron moderator 200' are separately utilized as a boundary for two different flow channels 602 (except for those neutron moderators 200' that are on the edge of the arrangement 600, which will only be utilized as a boundary for two or three different flow channels 602). In one or more embodiments, the first pair of neutron moderators 641 and the second pair of neutron moderators 651 may be configured to form a lattice pattern. [0081] In one or more embodiments, the resulting flow channel 602 may (in this case) be square. In other embodiments, by varying the size and/or placement of either the moderators 200 or 200', the resulting flow channels 602 may be characterized by a greater depth than width, defining a flow channel 602 with a rectangular cross section. Still in other embodiments, the resulting flow channels may be characterized by a greater width than depth, defining a flow channel 602 with a rectangular cross section. Thus, in at least one embodiment, by staggering the placement of the first neutron moderator pair 641 and the second neutron moderator pair 651, any number of configurations of flow channels 602 may be provided. In certain embodiments, the width of a flow channel 602 may correspond to the dimensions of the flow channel walls 604 and 608 (e.g., a face 225' of a neutron moderator 200' (as shown in FIG. 6B), or a face 225 of a neutron moderator 200), and the depth of the flow channel 602 may correspond to the dimensions of the flow channel walls 612 and 616 (e.g., a portion of a face 225' of a neutron moderator 200', or a face 225 of a neutron moderator 200 (as shown in FIG. 6B)). In one embodiment, the height of the flow channel 602 may correspond to the height 210' of the neutron moderator 200' or the height 210 of the neutron moderator 200. In certain embodiments, the width and the depth of the flow channel 502 may be configured to or tuned to achieve certain performance metrics.

[0082] Turning to FIG. 7, a top view of a neutron moderator arrangement 700 is shown, according to one embodiment of the present disclosure. In several embodiments, the arrangement 700 is substantially analogous to arrangement 600 of FIG. 6A and 6B, and includes, for example: a plurality of first neutron moderators, with multiple ones of moderator 200 (that are substantially analogous to the moderator 200 of FIG. 2A) and a plurality of second neutron moderators, with multiple ones of moderator 200' (that are substantially analogous to the moderator 200' of FIG. 2B), a first pair of neutron moderators 641 and a second pair of moderators 651, flow channels 602, flow channel walls 604, 608, 612, and 616, and engagement interfaces 620, 624, 628, and 632; redundant explanation of which is omitted for clarity. Notwithstanding the foregoing similarities, the arrangement 700 includes flow channels 602 that are offset from one another by an offset width 702. Although arrangement 700 of FIG. 7 is shown having certain numbers of neutron moderators 200 and 200', it will be appreciated that arrangement 700 may have any number of neutron moderators 200 and 200', including a number of neutron moderators 200 and 200' that may fill to capacity a reactor vessel. [0083] Turning now to FIGS. 8A and 8B, a perspective view and a cross-sectional view across line 8B-8B of FIG. 8 A of an example neutron moderator arrangement 800 is shown, according to one embodiment of the present disclosure. In various embodiments, arrangement

800 includes a plurality of neutron moderators, including multiple neutron moderator 801 components. In many embodiments, the arrangement 800 is substantially analogous to the arrangements 400, 500, 600, and 700, and each neutron moderator 801 is substantially analogous to the neutron moderators 200 and 200' of FIGS. 2A and 2B, except that the neutron moderators

801 may be characterized by an octagonal shape rather than a quadrilateral shape (and thus, neutron moderators 801 each include eight sides 890, each side 890 defining a generally planar face 892, rather than four sides 223 (or 223') and four faces 225 (or 225') of moderators 200 (or 200'). In some embodiments, each neutron moderator 801 may include some or all of the components and functionality of the neutron moderators 200 and 200' of FIGS. 2 A and 2B. Although arrangement 800 of FIGS. 8A and 8B is shown having certain numbers of neutron moderators 801, it will be appreciated that arrangement 800 may have any number of neutron moderators 801, including a number of neutron moderators 801 that may fill to capacity a reactor vessel. The perspective view of the arrangement 800 illustrated in FIG. 8A is for purposes of illustration only. The neutron moderators 801 may generally be arranged within a reactor vessel such that respective flow channels of the arrangement 800 extend in a vertical direction; however, in other examples, the flow channels may extend in any appropriate direction as needed for a given application.

[0084] In multiple embodiments, the neutron moderators 801 of arrangement 800 may be attached to a gridplate and arranged to form a first pair of neutron moderators 841 and a second pair of neutron moderators 851. In some embodiments, at least a portion of a respective face of each neutron moderator 801 in the first pair of neutron moderators 841 and a respective face of each neutron moderator 801 in the second pair of neutron moderators 8851 may be on a single side of a respective neutron moderator 801. In many embodiments, at least a portion of a respective face of each neutron moderator 801 in the first pair of neutron moderators 841 and a respective face of each neutron moderator 801 in the second pair of neutron moderators 851 may define a flow channel 802. In certain embodiments, the first pair of neutron moderators 841 and the second pair of neutron moderators 851 may be arranged to cooperate to form a lattice pattern in a plane perpendicular to the flow channel 802. Specifically, in one embodiment, the neutron moderators 801 of the first pair 841 are opposite each other across the flow channel 802, and the neutron moderators 801 of the second pair 851 are opposite each other across the flow channel 802 and adjacent to the moderators 801 of the first pair 841.

[0085] In several embodiments, as shown in FIG. 8B, the flow channel 802 may be specifically defined by flow channel walls 804, 808, 812, and 816. In at least one embodiment, the flow channel walls 804, 808, 812, and 816 may be defined by an entire face 892 of the moderator 801. In one or more embodiments, the arrangement 800 may also include engagement interfaces 820, 824, 828, and 832. In certain embodiments, the engagement interfaces 820, 824, 828, and 832 may be defined by an interface of two faces 892 of two adjacent moderators 801, and may be a connection or contact between adjacent moderators 801 , such as a moderator 801 of the first pair 841 and a moderator 801 of the second pair 851.

[0086] Turning now to FIG. 9, a cross-sectional view of a reactor vessel 900 is shown, according to one embodiment of the present disclosure. In several embodiments, the reactor vessel 900 may include a reactor vessel wall 901 having an interior surface 902 and an exterior surface 903, and also having a certain volume. In many embodiments, the reactor vessel 900 may also include the arrangement 700 (or any other arrangement as described herein or other arrangement possibilities), transition neutron moderators 904, and a gridplate (not shown in FIG. 9, but similar to the gridplate shown in FIGS. 11 A and 1 IB). In one or more embodiments, the arrangement 700 may be substantially analogous to arrangement 700 of FIG. 7. In at least one embodiment, the gridplate may arrange the neutron moderators 200 and the plurality of second neutron moderators 200' within the reactor vessel 900 to form a lattice configuration, such as any of the lattice configurations described herein. In one or more embodiments, the gridplate may also arrange the transition neutron moderators 904 along the interior surface 902 and around a periphery 905 of the arrangement 700.

[0087] In several embodiments, the transition neutron moderators 904 may include a vessel interface 908 that substantially conforms to the shape of the interior surface 902. In at least one embodiment, the transition neutron moderators 904 may also include an internal wall 907 that substantially conforms to a shape defined by the arrangement 700, and the transition neutron moderators 904 may contact the arrangement 700 at a contact point 906. In the embodiment shown in FIG. 9, the transition neutron moderators 904 allow the arrangement 700 to have a substantially quadrilateral cross section while in the reactor vessel 900 that has a round crosssection. In one or more embodiments, the transition neutron moderators 904 may be of a similar shape but different sizes, as needed to allow the arrangement 700 to have the quadrilateral cross section within the reactor vessel 900 having a circular cross section. In some embodiments, the transition neutron moderators 904 may be substantially analogous to the neutron moderators 200 and 200' of FIGS. 2A and 2B, except that the transition neutron moderators 904 have an archshaped cross section rather than a square or rectangle cross section.

[0088] Turning to FIG. 10, a top cross-sectional view of an example reactor vessel 1000 is shown, according to one embodiment of the present disclosure. In multiple embodiments, the reactor vessel 1000 may include a reactor vessel wall 1001 having an interior surface 1003, and a gridplate (as shown in FIGS. 11 A and 1 IB). In many embodiments, the reactor vessel 1000 also includes the nuclear moderator arrangement 700 (though it could be any other arrangement as described or contemplated herein), and a plurality of transition neutron moderators, multiple ones of moderator 1002. In one or more embodiments, arrangement 700 is substantially analogous to arrangement 700 of FIG. 7A. In some embodiments, the gridplate may arrange arrangement 700 within the reactor vessel 1000 to form a lattice configuration, such as any of the lattice configurations described herein. In at least one embodiment, the gridplate may also arrange the transition neutron moderators 1002 along the interior surface 1003. In one or more embodiments, each transition neutron moderator 1002 may be substantially analogous to the neutron moderators 200 and 200' of FIGS. 2A-2D. Notwithstanding the foregoing, the transition neutron moderators 1002 may have larger or smaller dimensions than moderators 200 and 200' of FIGS. 2A-2D. In certain embodiments, the transition neutron moderators 1002 may be manufactured from the same or different materials as the neutron moderators 200 and 200' of FIGS. 2 A and 2B.

[0089] In several embodiments, each transition neutron moderator 1002 may include at least one vessel wall 1003 that substantially conforms to the shape of the interior surface 1003 and an internal wall 1004 that substantially conforms to a shape defined by arrangement 700. In one or more embodiments, the transition neutron moderators 1002 may also include at least one transition wall 1005 that substantially conforms to a shape defined by the adjacent transition neutron moderators 1002. In the embodiment shown in FIG. 10, the reactor vessel 1000 includes a quadrilateral cross section. In some embodiments, the quadrilateral cross section may allow each of the transition neutron moderators 1002 to include a substantially rectangular crosssection. In many embodiments, the vessel wall 1003 and the internal wall 1004 therefore define a transition between the interior surface 1003 of the vessel wall 1001 and the arrangement 700. In this embodiment, because each of the transition neutron moderators 1002 may include a rectangular cross-section, little to no machining of each transition neutron moderators 1002 may be required.

[0090] Turning to FIGS. 11 A and 1 IB, two side views of an example gridplate are shown, according to one embodiment of the present disclosure. With reference to FIG. 11 A, a gridplate 1100 is shown, which may be included in a reactor vessel, such as the reactor vessel 900 in FIG.

9 or the reactor vessel 1000 in FIG. 10. In some embodiments, the gridplate 1100 may include connection areas 1106 configured to receive the neutron moderators 1101, and specifically the connector body 1102. In at least one embodiment, the neutron moderators 1101 may be substantially analogous to the neutron moderators 200 and 200' in FIGS. 2A and 2B and include similar components and features such as a connector body 1102.

[0091] In several embodiments, the gridplate 1100 may substantially conform to the shape of the reactor vessel. For example, in relation to FIG. 9, the gridplate 1100 may be substantially round. In relation to FIG. 10, the gridplate 1100 may be rectangular. In some embodiments, the connection areas 1106 may be configured to allow for any number of arrangements of neutron moderators 1101. For example, in one embodiment, the connection areas 1106 may be configured to arrange the neutron moderators 1101 in an evenly spaced arrangement, whereby pairs of neutron moderators 1101 form lattice configurations, as in FIGS. 4A and 4B. In other embodiments, the connection areas 1106 may alternatively be configured to arrange the neutron moderators 1101 to form a triangular lattice configuration with offset flow channels, as is shown in FIG. 7. The preceding is not exhaustive; the gridplate 1100 (and connection areas 1106) may be configured to form any of the neutron moderator arrangements shown or described above in any reactor vessel.

[0092] In multiple embodiments, the connection areas 1106 may be further configured to receive one or more type of connector body 1102 by press fit, threaded connection, or any other suitable connection. In some embodiments, the connection area 1106 may include a fastener 1108 to secure the connector body 1102. In some embodiments, the connection areas 1106 may all receive the same connection type. Tn other embodiments, the connection area 1106 may receive differing connection types.

[0093] In one or more embodiments, the gridplate 1100 may maintain the plurality of neutron moderators 1101 in an evenly spaced arrangement, whereby pairs of neutron moderators 1101 form lattice configurations, as in FIGS. 4A and 4B. In many embodiments, and with reference to FIG. 11B, a gridplate 1100' may allow the connector body 1102 of a neutron moderator 1101 to pass through the connection area 1106 of the gridplate 1100'. In some embodiments, the connector body 1102 may connect to the connection area 1106 by threaded connection or any other suitable fastening system. In at least one embodiment, the gridplate 1100' may include the fastener 1108 to assist in fastening the connector body 1102 to the connection area 1106. Notwithstanding the foregoing, the gridplate 1100' of FIG. 11B may be substantially analogous to the gridplate 1100 described above in relation to FIG. 11 A. In any embodiment, the gridplates 1100, 1100' may be configured to form any of the neutron moderator arrangements shown or described above in any reactor vessel.

[0094] Turning to FIG. 12, a perspective view of an example gridplate 1200 is shown, according to one embodiment of the present disclosure. In various embodiments, the gridplate 1200 can connect to a plurality of neutron moderators (not shown in FIG. 12), such as neutron moderators 200 and 200' as shown in FIGS. 2A and 2B. In at least one embodiment, the gridplate 1200 may be shaped to fit a reactor vessel. For example, in one embodiment, the gridplate 1200 may be generally round as is shown in FIG. 12, and thus fit in a round reactor such as the reactor vessel 900 in FIG. 9. In other embodiments, the gridplate 1200 may alternatively be polygonal as may be required in the reactor vessel 1000 in FIG. 10.

[0095] In one or more embodiments, the gridplate 1200 may be substantially analogous to the gridplates 1100, 1100' in FIGS. HA and 11B. In several embodiments, the gridplate 1200 may include a plurality of first partitions 1203 and a plurality of second partitions 1204, in which the plurality of second partitions 1204 are perpendicular to the plurality of first partitions 1203. In many embodiments, the plurality of first partitions 1203 and the plurality of second partitions 1204 bisect each other to create individual grid cells 1201. In some embodiments, the individual grid cells 1201 include the connection area 1206. [0096] In one or more embodiments, the gridplate 1200 may be configured to maintain the plurality of neutron moderators in a pattern such that flow channels are created in a lattice pattern, such as in any of the lattice patterns or configurations described herein. In at least one embodiment, the connection areas 1206 may be utilized to connect or fasten the connector body of a neutron moderator to the gridplate 1200. In many embodiments, the desired pattern may form flow channels (not shown) defined by at least a portion one or more faces of pairs of the neutron moderators.

[0097] In various embodiments, although the grid cells 1201 are shown as being arranged in a uniform manner, other embodiments are contemplated. For example, in one embodiment, the grid cells 1201 may be manufactured in the gridplate 1200 in various regions characterized by a different connection area-density. In at least one embodiment, the grid cells 1201 may be arranged by changing the amount of either the plurality of first partitions 1203 or the plurality of second partitions 1204. In some embodiments, as a result, the plurality of neutron moderators may form a pattern characterized by larger flow channels in a center of the gridplate 1200, and narrower flow channels at the edges of the reactor core structure. Such a pattern may be determined to optimize thermal performance of the reactor core, or optimize other metrics.

[0098] Turning now to FIG. 13, an example method 1300 of constructing a reactor system is described, according to one embodiment of the present disclosure. In multiple embodiments, at step 1302, a reactor vessel is provided, wherein the reactor vessel defines a reactor vessel volume. In many embodiments, the reactor vessel may be similar to the reactor vessel 900 in FIG. 9 or the reactor vessel 1000 in FIG. 10. Thus, in one embodiment, the reactor vessel may include a round cross-section or a rectangular cross-section. In some embodiments, the reactor vessel may include any polygonal cross-section.

[0099] In multiple embodiments, at step 1304, a support structure is arranged within the reactor vessel volume. In at least one embodiment, the support structure may be similar to the gridplate 1100 in FIG. 11 A. In some embodiments, the support structure may include a series of mounts (similar to the connection areas 1106 of FIG. 11A or 1206 of FIG. 12, or the grid cells 1201 of FIG. 12), configured to secure one or more neutron moderators to the support structure.

[0100] In several embodiments, the series of mounts may be configured to receive the one or more neutron moderators through press fit, threaded connection, or any other suitable connection type. In many embodiments, the series of mounts may include a fastener to secure the one or more neutron moderators. In some embodiments, the series of mounts may all receive the same connection type. In other embodiments, the series of mounts may receive differing connection types.

[0101] In various embodiments, the one or more neutron moderators may be substantially analogous to the neutron moderators 200 and 200' in FIGS. 2A-2D. Thus, respective faces of the one or more neutron moderators may be flat, requiring machining only to the extent required to initially cut or shape the structure to the desired dimensions. In some cases, the flat surface may be machined (e.g., polished), although no drilling of holes is required. In some embodiments, the one or more neutron moderators may have a cross-section that is rectangular (as shown in FIG. 2B), octagonal (as shown in FIGS. 8 A and 8B), triangular, or any other polygonal shape, or may be circular.

[0102] In several embodiments, the one or more neutron moderators may be configured to achieve a certain set of performance metrics, both individually and when used as part of an arrangement of neutron moderators within a reactor core. In many embodiments, the performance metrics may include a thermal or epithermal neutron spectrum, other thermal metrics, and other relevant metrics. In at least one embodiment, the performance metrics may be achieved by adjusting parameters associated with the one or more neutron moderator including the shape of the one or more neutron moderators, a body height, a body width, the body depth, and the composition of the neutron moderator, (e.g., graphite, beryllium, etc.).

[0103] In multiple embodiments, at step 1306, a first pair of neutron moderators may be attached to the support structure. In certain embodiments, the first pair of neutron moderators may be attached to the support structure via a connector body such as the connector body 202 in FIGS. 2A-2D. In at least one embodiment, the connector body may be received by the series of mounts and may be secured by a fastener.

[0104] In one or more embodiments, at step 1308, a second pair of neutron moderators may be attached to the support structure. In many embodiments, the first pair of neutron moderators may be attached to the support structure via a connector body such as the connector body 202 in FIGS. 2A-2D. In some embodiments, the connector body may be received by the series of mounts and may be secured by the fastener. In at least one embodiment, after being attached, at least a portion of a respective face of each neutron moderator of the first pair of neutron moderators and each neutron moderator of the second pair of neutron moderators define a flow channel through the reactor vessel volume.

[0105] In multiple embodiments, the method 1300 may also include an optional step 1310 of maintaining an arrangement of the first and second pairs of neutron moderators in a lattice configuration (e.g., a square, rectangular, triangular, hexagonal, or other regular lattice configuration) on a plane perpendicular to the flow channel. In some embodiments, the arrangement of neutron moderators may create an evenly spaced arrangement, whereby pairs of neutron moderators form a lattice structure, as in FIGS. 4A and 4B. In an alternative embodiment, the pairs of neutron moderators may be configured to arrange the neutron moderators to form a triangular lattice with offset flow channels, as is shown in FIG. 7. In many embodiments, the preceding is not exhaustive; the method 1300 may be used to form any of the neutron moderator arrangements shown or described above in any reactor vessel.

[0106] Aspects, features, and benefits of the systems, methods, processes, formulations, apparatuses, and products discussed herein will become apparent from the information disclosed in the exhibits and the other applications as incorporated by reference. Variations and modifications to the disclosed systems and methods may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

[0107] It will, nevertheless, be understood that no limitation of the scope of the disclosure is intended by the information disclosed in the exhibits or the applications incorporated by reference; any alterations and further modifications of the described or illustrated embodiments, and any further applications of the principles of the disclosure as illustrated therein are contemplated as would normally occur to one skilled in the art to which the disclosure relates.

[0108] The foregoing description of the example embodiments has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the inventions to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

[0109] The embodiments were chosen and described in order to explain the principles of the inventions and their practical application so as to enable others skilled in the art to utilize the inventions and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present inventions pertain without departing from their spirit and scope. Accordingly, the scope of the present inventions is defined by the appended claims rather than the foregoing description and the example embodiments described therein.

[0110] While various aspects have been described in the context of a preferred embodiment, additional aspects, features, and methodologies of the claimed inventions will be readily discernible from the description herein, by those of ordinary skill in the art. Many embodiments and adaptations of the disclosure and claimed inventions other than those herein described, as well as many variations, modifications, and equivalent arrangements and methodologies, will be apparent from or reasonably suggested by the disclosure and the foregoing description thereof, without departing from the substance or scope of the claims. Furthermore, any sequence(s) and/or temporal order of steps of various processes described and claimed herein are those considered to be the best mode contemplated for carrying out the claimed inventions. It should also be understood that, although steps of various processes may be shown and described as being in a preferred sequence or temporal order, the steps of any such processes are not limited to being carried out in any particular sequence or order, absent a specific indication of such to achieve a particular intended result. In most cases, the steps of such processes may be carried out in a variety of different sequences and orders, while still falling within the scope of the claimed inventions. In addition, some steps may be carried out simultaneously, contemporaneously, or in synchronization with other steps.

[0111] The embodiments were chosen and described in order to explain the principles of the claimed inventions and their practical application so as to enable others skilled in the art to utilize the inventions and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the claimed inventions pertain without departing from their spirit and scope. Accordingly, the scope of the claimed inventions is defined by the appended claims rather than the foregoing description and the example embodiments described therein.

Claims

CLAIMS What is claimed is:

1. An arrangement of neutron moderator structures comprising a first pair of neutron moderator; a second pair of neutron moderator cooperating with the first pair of neutron moderators to define a flow channel with at least a portion of a face of each neutron moderator of the first pair of neutron moderators, and each neutron moderator of the second pair of neutron moderators, wherein the first pair of neutron moderators and the second pair of neutron moderator structures are arranged to define a lattice configuration in a reactor vessel and along a plane perpendicular to the flow channel.

2. The arrangement of claim 1, wherein each neutron moderator of the first pair of neutron moderators comprises an elongated neutron moderator body defining four sides, each side of the four sides connected to one another to define a perimeter of the respective neutron moderator of the first pair, each side extending along an elongated direction of the elongated first neutron moderator body.

3. The arrangement of claim 2, wherein each neutron moderator of the second pair of neutron moderators comprises an elongated second neutron moderator body defining four sides, each side of the four sides connected to one another to define a perimeter of the respective neutron moderator of the second pair, each side extending along an elongated direction of the elongated second neutron moderator body.

4. The arrangement of claim 3, wherein the at least a portion of a face of each neutron moderator of the first pair of neutron moderators, and each neutron moderator of the second pair of neutron moderators is on a single side of a respective neutron moderator structure.

5. The arrangement of claim 4, wherein each side of the four sides of each neutron moderator of the first pair of neutron moderators has a width that is uniform along the elongated direction and that is uniform with the other sides of the respective neutron moderator to define a square cross-section.

6. The arrangement of claim 5, wherein each side of the four sides of each neutron moderator of the second pair of neutron moderators has a width that is uniform along the elongated direction and that is uniform with the other sides of the respective neutron moderator to define a square cross-section.

7. The arrangement of claim 4, wherein the flow channel has a rectangular crosssection defined by an entire surface area of a respective side of each neutron moderator of the first pair of neutron moderators, and a portion of the surface area of a respective side of each neutron moderator of the second pair of neutron moderators.

8. The arrangement of claim 4, wherein each neutron moderator of the first pair of neutron moderators has a first cross-sectional shape, each neutron moderator of the second pair of neutron moderators has a second cross- sectional shape, and the first pair of neutron moderator structures and the second neutron moderator structures cooperate with one another to define the flow channel as having a rectangular cross-section.

9. The arrangement of claim 1, wherein the at least a portion of the face of each neutron moderator of the first pair of neutron moderators and each neutron moderator of the second pair of neutron moderators comprises a generally planar region of the respective neutron moderator structure.

10. The arrangement of claim 1, wherein the generally planar region comprises a flat surface of the respective neutron moderator.

11. The arrangement of claim 1, wherein each neutron moderator of each of the first pair of neutron moderators and the second pair of neutron moderators comprises at least one connector body arranged at an end of a respective neutron moderator, and the at least one connector body is configured to mount the respective neutron moderator in a gridplate of the reactor vessel.

12. A reactor vessel system comprising: a reactor vessel defining a reactor vessel volume; and the arrangement of neutron moderator structures of claim 1 arranged in the reactor vessel volume.

13. The reactor vessel system of claim 12, comprising a gridplate in the reactor vessel and arranging each neutron moderator of the first pair of neutron moderators and the second pair of neutron moderators in the lattice configuration.

14. The reactor vessel system of claim 12, wherein the reactor vessel has a substantially rectangular cross-section along an elongated length of the reactor vessel, and the reactor vessel system comprises a peripheral neutron moderator structure having a substantially rectangular cross-section and defining a transition between an interior surface of the reactor vessel and one or more neutron moderators of the first pair of neutron moderator structures or the second pair of neutron moderator structures.

15. A reactor vessel system comprising a reactor vessel defining a reactor vessel volume; a first pair of neutron moderators; and a second pair of neutron moderators cooperating with the first pair of neutron moderator structures to define a flow channel therebetween with a least a portion of a non-machined face of each neutron moderator of the first pair of neutron moderators and the second pair of neutron moderators.

16. The reactor vessel system of claim 15, wherein the vessel defines an elongated structure having a first end and a second end opposite the first end, and the flow channel has a square or rectangular cross-section along an entire length of each neutron moderator of the first pair of neutron moderators and the second pair of neutron moderators between the first end and the second end.

17. The reactor vessel system of claim 15, wherein the first pair of neutron moderators and the second pair of neutron moderators are neutron moderators of a plurality of neutron moderators, the plurality of neutron moderators defines, collectively, a plurality of flow channels, and the plurality of flow channels establishes, collectively, a lattice configuration on a plane perpendicular to the plurality of flow channels.

18. The reactor vessel system of claim 15, wherein the reactor vessel comprises a rectangular cross-section, and the plurality of neutron moderators comprises a sub-plurality of neutron moderators about a periphery of the plurality of neutron moderators arranged to define an interface with flat, internal surfaces of the reactor vessel along the rectangular cross-section.

19. A method of constructing a reactor system, the method comprising providing a reactor vessel, the reactor vessel having a reactor vessel volume; arranging a support structure within the reactor vessel volume, the support structure having a series of mounts configured to secure neutron moderators thereto; securing a first pair of neutron moderators to the support structure; and securing a second pair of neutron moderators to the support structure such that at least a portion of a face of each neutron moderator of the first pair of neutron moderators and the second pair neutron moderators define a flow channel through the reactor vessel volume.

20. A method of claim 19, furthering comprising maintaining the arrangement of the first pair of neutron moderators and the second pair of neutron moderators in a lattice configuration on a plane perpendicular to the flow channel.